Carbohydrate content of black liquor and precipitated lignin at different ionic strengths in flow-through kraft cooking
Artikel i vetenskaplig tidskrift, 2018

The influence of sodium ion concentration [Na+] on the dissolution of carbohydrates in black liquor (BL) during flow-through kraft cooking of Scots pine wood meal (Pinus sylvestris) was studied. Fractions of BL were collected at different times and the carbohydrate content of the various fractions was analysed. Lignin was precipitated from the BL by lowering the pH, and the carbohydrate content of the precipitated lignins (Lprec) was also examined. The molecular weight distribution (MWD) of the Lprecsamples was analysed. Xylose (Xyl) was found to be the most predominant sugar in BL aside from arabinose (Ara) and galactose (Gal), while the amounts of these sugars decreased with increasing levels of [Na+] in the cooking liquor. The minor amounts of mannose (Man) found in BL was not influenced by the [Na+]. The effects of NaCl and Na2CO3on the carbohydrate dissolution were similar, but slightly lower concentrations of Ara and Xyl were found in the case of NaCl application. All of the Lprecsamples contained some carbohydrate residues, the contents of which increased with increasing cooking time and decreased with higher [Na+]. It can be concluded that arabinoglucuronoxylan (AGX) along with arabinogalactans (AG) and arabinan, are covalently linked to lignin. The glucose (Glc) residue detected in Lprecmay originate from 1,3-β-glucan linked to lignin.

softwood

ionic strength

precipitated lignin

kraft cooking

sodium ion concentration

flow-through reactor

black liquor

Författare

Binh Dang

Chalmers, Kemi och kemiteknik, Kemiteknik, Skogsindustriell kemiteknik

Harald Brelid

Chalmers, Kemi och kemiteknik, Kemiteknik, Skogsindustriell kemiteknik

Södra Innovation

Hans Theliander

Chalmers, Kemi och kemiteknik, Kemiteknik, Kemisk reaktionsteknik

Wallenberg Wood Science Center (WWSC)

Holzforschung

0018-3830 (ISSN) 1437-434X (eISSN)

Vol. 72 7 539-547

Ämneskategorier

Livsmedelsvetenskap

Pappers-, massa- och fiberteknik

Växtbioteknologi

DOI

10.1515/hf-2017-0146

Mer information

Senast uppdaterat

2018-09-19